Larger motor vehicles, such as trucks, are nowadays designed with relatively high ground clearance. A principal reason for this lies in the need to be able to use the vehicle when driving on uneven surfaces, for example.
The fact that a truck normally has a relatively high ground clearance, however, constitutes a risk in terms of road safety. This is due to the fact that in a possible head-on collision between a truck and a passenger car there is a risk that the front section of the passenger car will run in under the front of the truck and thus become wedged fast between the roadway and the underside of the front of the truck. This can lead to the front of the truck penetrating the passenger compartment of the car with great force. In even more unfortunate cases, the truck can continue forward and roll over the passenger car.
One solution to this problem is to provide the truck with special underrun protection in the form of a reinforced structure, such as a force-absorbing beam element, which is arranged horizontally at the front of the truck. This beam element is more specifically arranged in a position corresponding to an anticipated stress from a force in the event of a collision with a passenger car. Such an element can serve to prevent the passenger car running in under the front of the truck.
Vehicles are manufactured in various designs depending on the sphere of application in which the vehicle is to be used. This means that vehicles having the same frame and cab construction may be designed with different frame heights. In order to provide an effective underrun protection, the position of the underrun protection must be adjusted according to the frame height of the vehicle. In order to ensure that common components can be used for vehicles with different frame heights, a lower transverse beam has been added to an upper transverse beam forming an impact element in an underrun protection fitted to the vehicle.
It has emerged that fitting the lower transverse beam to the upper transverse beam is complicated. This is due partly to the fact that the upper transverse beam is somewhat inaccessible after the vehicle cab has been fitted, and partly to the fact that the connection between the existing impact element and the lower transverse beam must be very strong, since it is exposed to very large forces in the event of a collision.